1. Field of the Invention
This invention relates to air disconnect switches and particularly to air disconnect switches with which a load break interrupter is associated.
2. Description of the Prior Art
Growth of load densities and environmental requirements indicates a need for disconnect switches which incorporate a load break switch that operates reliably with long life and minimum maintenance. The disconnect switch device must also operate with a minimum of noise and eliminate the arcing characteristics usually associated with disconnect switches and of course must be capable of being manufactured at a reasonable cost.
Switches to which the present invention relates are known in the art. The prior art devices operate to first effect initial opening of the interrupter and subsequently effect the opening of the related disconnect blade to thereby completely isolate the circuit. Such an arrangement is disclosed in U.S. Pat. Nos. 2,769,063 and 2,889,434.
U.S. Pat. No. 2,737,556 illustrates a device which utilizes oil as the arc extinguishing medium, while U.S. Pat. No. 2,810,805 discloses a vacuum device arrangement.
All of the known types of interrupter switches utilize the disconnect switch arm to actuate the interrupter. At higher voltages the operating linkages become large and are mechanically unreliable, especially under icing conditions. Higher reliability at low cost can be realized with the arrangement herein set forth. In the present device herein set forth, improvements have been made in a medium capacity interrupter device to make it particularly suitable for interruption operation for ratings of up to and including 230 KV -- 600 A; and having complete insulation strength between the open contacts at full rating; and having circuit interruption capabilities in pressurized sulfur hexafluoride which eliminates arcing and reduces noise level during operation. The present interrupter has a completely sealed mechanism actuator which is through linkage tightly coupled to the switch blade mechanism, providing positive drive. Also improvement in the current transfer horns have been accomplished which are self-cleaning of ice and self-polishing of oxidation.